1. Field of the Invention
The present invention relates to a treatment system for treating a source liquid and more particularly to such a system having a dispenser for dosing a treating liquid into the source liquid.
2. Description of the Prior Art
There are many systems where it is desired to treat a liquid, hereinafter referred to as a source liquid, with a liquid treating agent to modify the source liquid and produce a modified source liquid having certain desired properties. One example of this is an aerobic wastewater treatment system (AWTS) which generally comprises a settling or trash tank to remove most solids, an aerobic treatment tank to treat the effluent from the solids separation tank and aerobically digest the bulk of remaining solids and a pump or holding tank for receiving the effluent from the aerobic treatment tank. Generally speaking, the holding tank, commonly referred to as a pump tank, receives a substantially solids free wastewater (SSFW) which can be removed from the holding tank, usually by a pump, and disposed of into a stream, sprayed on vegetation, introduced into a drain field, etc.
In these AWTS, it is sometimes necessary that the SSFW's be disinfected prior to leaving the system. To this end, disinfecting systems, e.g., chlorinators, which can be either solid or liquid, have been employed to introduce a disinfectant into the SSFW prior to or concurrent with the removal of the SSFW from the holding tank.
Whether the disinfecting agent be a solid or a liquid, a requirement is that the SSFW to be pumped or otherwise removed from the system must be in contact with the disinfecting agent for a sufficient period of time to ensure that the SSFW is substantially free of bacteria.
Conventionally, prior art disinfectant systems for use in AWTS, whether employing a liquid or solid disinfectant, typically mix the disinfectant with the SSFW as the SSFW is being pumped out of the holding tank. Indeed, most presently used liquid disinfectant systems for AWTS employ a Venturi system to draw the liquid disinfectant from containers of the disinfectant and into the holding/pump tank. The Venturi based systems necessarily introduce the disinfectant into the pump tank while the pump is discharging liquid from the pump tank meaning the desired degree of residence or contact time between the disinfectant and SSFW may not be realized.
Additionally, the Venturi based systems frequently introduce an excessive amount of disinfectant into the SSFW resulting in waste of disinfectant and damage to vegetation or wildlife if the disinfected water is sprayed on the vegetation introduced into a drain field or pumped to a drainage ditch, canal, creek or the like. Lastly the Venturi based systems are prone to plugging from fine solids carried over from the aerobic treatment tank.